90+2 That is it from Old Trafford and the final whistle goes.
Fluffed back pass from Evra has a few heart's fluttering in the crowd but the danger is cleared by an alert Jonny Evans.
Great last-ditch defence from Man United as two players dive in to block a shot from Nolan.
There will be three added minutes at Old Trafford.
Jones goes for a precise finish from the edge of the West Ham area but it is deflected behind for a corner.
Quick break by the home team but Welbeck dallies on the edge of the box and West Ham get players back. He passes to rafael down the right but his cross is poor and easily cleared.
Maiga has a good effort from the right side of the Man United box as he cuts on to his left foot and just fires over the bar.
Young flattened by Demel and he wins a free-kick.
83 Another sub for the hosts as Phil Jones comes on for Anderson.
Cole should have got West Ham level. Another deep free-kick from halfway by Collins drops in the Man United box. Cole swivels and shoots from close range and some how Lindegaard gets down to save.
Good burst from midfield by Anderson but his touch lets him down badly as he gets into the West Ham area and the ball rolls through to Jaaskelainen.
Welbeck's first contribution is to head behind his own goal after a dangerous cross from the right by West Ham.
76 Rooney off and Welbeck on.
76 Carrick goes in the book for Manchester United after a foul in midfield.
75 O'Neil is on for West Ham and he replaces Diame.
Van persie nearly doubles the home side's lead as he is put in the clear by Rooney but he just fails to get his shot away before the challenge of Demel arrives.
Gary O'Neil getting ready to come on for the Hammers.
68 More good stuff on the edge of the West ham area and Rooney fires just over. Another change Jarvis goes off for West Ham and is replaced by Modibo Maiga.
Rafeal flashes a volley goalward but it just can't find a vital touch to force it into the West Ham net.
Great delivery from the West Ham free-kick and Tomkins looks like he should do better at the back post with a header.
63 Demel goes down under a challenge from Anderson and West Ham get a free-kick. Play stops and Ashley Young comes on for Cleverley.
Cole and Evans bump into one another in the Man United box and Evans is down. He is soon back on his feet and it was nothing sinister.
Anderson's radar is off and his pass down the left flank goes out for a West Ham throw much to the disgust of the home fans.
61 West Ham make a change and Carroll is replaced by Carlton Cole.
Great attempt from Rooney from the left edge of the West ham Box. Jaaskelainen at full stretch to push the ball behind for a corner. The hosts nearly scramble the ball home from the restart but it is hacked clear via Nolan and eventually Carroll.
The home side once again forced to shoot from distance as the ball breaks tio Carrick 30 yards from goal and his effort is well wide.
Jaaskelainen makes the save from the free-kick taken by van Persie.
Free-kick on the edge of the West Ham area to the hosts as van Persie is brought down by O'Brien.
Cleverley beats a host of players on the edge of the West Ham area but his shot thuds into Tomkins.
Super cross from the right by Rooney and Hernandez just fails to get his head on the ball six yards out as Collins clears.
Man United in full protest mode as Cleverley's shot from the edge of area fizzes over the bar. They think Jaaskelainen has got a touch but he doesn't, nor does the ref and it is a goal-kick.
Super cross from the right by Demel but Carroll can't bring the ball under control in the centre.
Room for Rooney on halfway but Tomkins makes a good challenge and halts his progress.
Another corner for the Hammers but that is cleared easily.
Early chance for Diame as the ball breaks kindly for him in the Man United box but his shot hits Smalling and loops behind for a corner.
West Ham get the second half going.
Manchester United are not expected to let this lead slip, but Sky Bet offer odds of 8/1 that West Ham can salvage a draw here. They're 33/1 to turn the game on its head and steal a win, while the leading hosts can still be backed at 1/12. Javier Hernandez is good value at 9/2 to score the next goal, with Andy Carroll (12/1) deemed the most likely Hammer to score next.
45+1 Sir Alex heads for the dressing room and the whistle goes for the interval.
Late headed chance for van Persie but it takes a deflection and is easily gathered by Jaaskelainen.
There will be one added minute.
Rooney flicks a nice ball through to Hernandez but the Mexican has strayed offside as he chases the ball into the West Ham area.
Great ball from Anderson to Hernandez in the inside left channel but he is well challenged by Collins in the West Ham area and the ball is behind for a goal-kick.
West Ham's threat has diminished in the last five minutes or so as the home side continue to probe for that second goal.
Evra well found by Persie on the left side of the West Ham box but the former drills his cross way to hard over the heads of a handful of red shirts waiting with anticipation.
A quick update from Sky Bet: "West Ham are by no means out of sight just yet, and we currently go 8/1 that they can come away from this with a draw."
Great ball over the top finds van Persie clear in the West ham Box but he volleys wide as the offside whistle goes.
Steady build up from the home side and Anderson is encouraged to shoot from 30 yards by the home crowd - he wished he hadn't as he misses the target by a wide margin.
Clumsy tackle on Cleverley by Collins and Man United have a free-kick 35 yards from the West Ham goal. Van persie takes it, but it is rather tame and easily cleared.
Jaaskelainen called into making a much better save to his left as he thwarts Hernandez's attempt from the edge of the box.
Corner to Man United on their right is headed clear by Collins. The home side have possession again though and some neat play on the right leads to a shot from the edge of the area by Anderson which is saved.
James Tomkins is fouled by Carrick near halfway and another deep free-kick is fired into the Man United box. It drops for Carroll on the turn and his volley is just over. Should have hit the target.
Anderson tries to thread an optimistic ball through to Evra on the edge of the West Ham area but it is easily cut out by Diame.
Jarvis continues to do well down the left but his cross this time is too deep and goes behind for a Man United goal-kick.
Scuffed cross from the left is well collected by Cleverley in the West Ham box and he does well to centre - but there is no red shirt in the vicinity.
Another corner to West Ham is then punched clear by Lindegaard. It is fired back into the Man United box and this time Lindegaard can fall on the ball.
Collins takes a long free-kick from his own half into the Man United area and a volleyed attempt to clear by Patrice Evra leads to a West Ham corner.
Great cross from the left by Jarvis has the Man United defence at sixes and sevens but Anders Lindegaard comes off his line to punch clear to the edge of the box.
Carroll tries to control a high ball on the edge of the Man United area but Chris Smalling shows plenty of strength to get the better of the striker and clear.
Hernandez gets clear once again on the right and although he looks up as he enters the West Ham area, he decides to shoot and it goes well wide of the target.
Surging run through the centre by Rooney and his pass finds Hernandez down the right but but Guy Demel is in position to make a clearance.
Jarvis makes some progress down the left again but his pass to Mohamed Diame is just off target and intercepted.
Joey O'Brien is trapped on his own byline but manages to thump his clearance against van Persie and win his side a goal-kick.
A low free-kick is met at the near post by Nolan and his clever flick is just wide and into the side netting.
Rafael brings down Matt Jarvis on the left and West Ham have a good chance to get a good delivery into the box.
More good ground made down the right by Anderson but his cross is cleared from inside the West Ham area.
8 Tom Cleverley is fouled by Kevin Nolan about 30 yards from the West Ham goal but the free-kick comes to nothing and the Hammers have a chance for a breather. Nolan goes in the book though.
Another slick move from Manchester United down the right involving Wayne Rooney and Anderson but Javier Hernandez can't quite help the ball into the danger area.
West Ham's first effort on goal goes wide of the post from Andy Carroll. The home side's goal was timed at 33 seconds.
It is all Manchester United as they attack once again via Michael Carrick but an attempted cross into the box by van Persie is headed clear.
1 GOAL VAN PERSIE: The hosts are in front after the Dutchman tries to guide the ball into the back of the West Ham net but it takes a fortunate deflection off James Collins and loops over Jussi Jaaskelainen.
The home side get us started and are immediately on the attack down the left.
West Ham are a 10/1 shot with Sky Bet to upset the home side as overwhelming favourites Manchester United (2/9) aim to maintain their position at the top of the table with a home win. Even a draw (11/2) would be considered an upset, with most of the pre-game money going on Robin van Persie to open the scoring at 9/4. Sky Bet have a special double chance scorecast on offer, though, whereby the Dutchman scores first and United win either 1-0 or 2-0 at 9/1. Meanwhile, Andy Carroll to score first and the game to be drawn 1-1 is a long shot at 100/1.
The teams are in the tunnel and about to go out on to the pitch.
Here is West Ham: West Ham: Jaaskelainen, Demel, Reid, Collins, O'Brien, Taylor, Diame, Tomkins, Jarvis, Nolan, Carroll. Subs: Spiegel, Cole, Maiga, Spence, O'Neil, Moncur, Lletget.
Here is Manchester United: Lindegaard, Da Silva, Smalling, Evans, Evra, Carrick, Anderson, Cleverley, Rooney, van Persie, Hernandez. Subs: De Gea, Jones, Ferdinand, Young, Welbeck, Fletcher, Buttner.
Manchester United manager Sir Alex Ferguson has handed Anderson only his second Premier League start of the season. The Brazilian was among five changes for the leaders, with Javier Hernandez, Michael Carrick and Tom Cleverley also included, along with Chris Smalling, who replaced Rio Ferdinand alongside Jonny Evans in central defence. West Ham boss Sam Allardyce made four changes to the side beaten by Tottenham on Sunday, with Guy Demel, Matt Jarvis, Matt Taylor and James Collins all selected.
Hello and welcome along to our coverage tonight from Old Trafford. Teams to follow shortly ...
Kick-off is 2000 GMT.